As an example of such article storage facility described above, there is known an article storage facility having an article storage shelf with a purging function described below. This article storage shelf includes a plurality of storage sections for storing a transport container such as an FOUP, etc. accommodating a semiconductor wafer. Each storage section is provided with a feed nozzle as the inactive gas feeding section for feeding inactive gas such as nitrogen gas, argon gas, etc. to the inside of the transport container.
Japanese Unexamined Patent Application Publication No. 2010-16199 (Patent Document 1) discloses an example of such article storage facility. With this article storage facility, the flow rate of inactive gas to be discharged from the feed nozzle is varied between a case when a transport container is stored in the storage section and a case when no transport container is stored in the storage section.
More particularly, in Patent Document 1, an arrangement is provided such that the flow rate of inactive gas in the case of no transport container being stored in the storage section is set smaller (lower) than that in the case of a transport container being stored in the storage section. That is, the inactive gas flow rate in the case of a transport container being stored in the storage section is set to a flow rate (this is referred to as “a first flow rate”) required for feeding a sufficient amount of inactive gas into the transport container. Whereas, the discharging flow rate in the case of no transport container being stored in the storage section is set to a flow rate (this is referred to as “a second flow rate”) smaller than the first flow rate described above in order to prevent unwanted accumulation of impurity particles on the feed nozzle. With this arrangement, as compared with the case of discharging inactive gas at the first flow rate from the feed nozzle in the case also of no transport container being stored in the storage section, the consumption amount of inactive gas required for purging can be restricted, thus achieving cost reduction.
However, in Patent Document 1 above, the inactive gas is fed in a single feed manner that switches over the condition of feeding inactive gas at the first flow rate and the condition of feeding it at the second flow rate uniformly for all of the storage sections of the storage shelf. And, the flow rate of inactive gas in the case of no transport container being stored is set to the second flow rate which is a relatively small flow rate. For this reason, if a feed nozzle or the like as the inactive gas feeding section has been replaced and then an amount of inactive gas is to be fed therethrough for removing any impurity particles accumulated in this inactive gas feeding section, as the flow rate of the inactive gas is set to the second flow rate, the small amount of flow rate of inactive gas makes sufficient cleaning of the inactive gas feeding section impossible; or even it is possible, it will take a long time until sufficient removal of impurity particles is achieved.